Problem: Solve for $x$ : $9\sqrt{x} + 10 = 3\sqrt{x} + 5$
Solution: Subtract $3\sqrt{x}$ from both sides: $(9\sqrt{x} + 10) - 3\sqrt{x} = (3\sqrt{x} + 5) - 3\sqrt{x}$ $6\sqrt{x} + 10 = 5$ Subtract $10$ from both sides: $(6\sqrt{x} + 10) - 10 = 5 - 10$ $6\sqrt{x} = -5$ Divide both sides by $6$ $\frac{6\sqrt{x}}{6} = \frac{-5}{6}$ Simplify. $\sqrt{x} = -\dfrac{5}{6}$ The principal root of a number cannot be negative. So, there is no solution.